South African Branden Grace matched Spieth’s 67 to be four-under and fifth.

The Australian tilt is led by Jason Day but the Queenslander put a huge scare through the tournament when he collapsed on his final hole with a bout of vertigo before finishing his round of 70 to be two-under and tied 10th.

He is undergoing treatment and is no certainty to continue in Saturday’s third round.

Spieth reeled off four birdies in his opening eight holes to jump to the outright lead at six-under but handed it back with a double bogey as he made the turn.

His drive went into the sand and his attempted recovery caught the lip and went into deep rough prompting Spieth to call his strategy into question.

“This is the dumbest hole I’ve ever played in my life,” he said after the second shot.

His third found a greenside bunker and he was unable to get up and down, taking a double bogey six. From there birdies on the first and ninth holes were only tempered by a seventh hole three-putt bogey.

“I hit my three-wood better today. I’m not striking the driver in the middle of the face. But it’s something so minor, maybe a ball position.

“I’ll find it on the range. Playing with Spieth Day had two bogeys and just one birdie on the backside of the course before an incredible birdie on the first, his 10th.”

After a greenside bunker shot went across the green and down a massive slope Day was able to hole out for a miraculous birdie. He backed it up with a 30-foot birdie putt on the second and was just two off the lead.

A bogey on four was tempered by a birdie on eight before his physical collapse preceded a closing bogey.

Major rookie Cameron Smith is the next best Australian, one-under through nine holes to be one-under for the tournament and tied 14th.

Adam Scott is even par through four holes while former US Open champion Geoff Ogilvy shot a 72 to drop to one-over, where Marcus Fraser (nine holes) joins him.

John Senden sits at three over through six holes, on the current cut line while Kurt Barnes is four over through seven.

Marc Leishman shot a dismal 77 to finish at 10-over, heading for a missed cut, the same fate waiting former world No.1 Tiger Woods who backed up his miserable 80 with a 76 to finish 16-over.

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